NETRA: Cellphone-based Optometry Solution using Inverse Shack Hartmann Technique, from MIT Media Lab

http://cameraculture.media.mit.edu/
http://cameraculture.media.mit.edu/netra

NETRA: Interactive Display for Estimating Refractive Errors and Focal Range

MIT Media Lab researchers have created a quick, simple, and inexpensive way to use mobile phones to measure refractive errors of the eye, including nearsightedness, farsightedness, astigmatism, and age-related vision loss. Until now, these measurements have only been possible using specialized equipment operated by a trained professional.

This new system, called NETRA (Near-Eye Tool for Refractive Assessment), is a project of the Media Lab's Camera Culture research group. A small plastic device—which currently can be produced for less than US$2—is easily clipped onto a mobile phone screen. To use it, simply hold the device up to the eye, look into it, and use the phone's keypad until two patterns overlap. This is repeated several times per eye, with the patterns at different angles. The whole process takes about two minutes, during which time software loaded onto the phone computes and provides the data needed to create a prescription.

The small size and low cost of the device make it especially well-suited for use in the developing world. As many as two billion people worldwide have refractive errors of the eye, and according to the World Health Organization, these errors, left uncorrected, are the world's second-highest cause of blindness.

Category:

Science & Technology

Tags:

• optometry
• mit
• media
• lab
• cameraculture
• pamplona
• raskar
• mohan
• oliveira
• siggraph
• 2010
• shack
• hartmann

[cameraculturegroup]

Pl read the FAQ for the project. web.media.mit.edu/~pamplona/NE­TRA/

What netra does not do?

It does not replace your optometrist.

It does not use the camera in your cell phone.

It is not simply a reading chart on your cell phone display.

[otissumnerbrown]

The last exam that I was involved with cost $430. With intelligent use, this method, and your own trial-lens kit can produce an accurate measurement of the natural eye's refractive STATE. Enjoy.

[mizikal]

@psymansays an eye exam in my office is $43.00 and I can make glasses for as low as $45.00 . You cannot afford to spend $100.00 every two or three years? People tell me that all the time and I don't understand it. I don't make very good money but I can afford that.

[mizikal]

I am an optician and I think this is pretty neat. However, I will still need an RX from your eye Doctor to make you glasses.You can pay what you want for this but I will not make you glasses off of what your cell phone tells you. Besides an exam is not just about glasses. The Dr checks the health of the eye during the exam. This also will not work for contact lens wearers.

[psymansays]

@p0rt1337 Whatever, man. Some of us work hard for not much pay, and when it comes to either putting food on the table or $100 in an optometrist's pocket, well, guess what's gonna happen. Besides, the large group of people who don't require prescription glasses don't have to see an optometrist all the time, and they don't have any higher incidence of eye problems from not paying some yuppie in a lab coat every year or two.

[psymansays]

Could this be ported to work on a PC? Linux? Please? I've been unable to afford to update my prescription for several years, and my current pair of glasses are nearly 10 years old! They're so scratched up...

[p0rt1337]

Also if people start using this INSTEAD of having regular eye checks, then more and more people may risk sight threatening conditions. People forget that an eye test not only checks your visual acuity, but also a full health check of the back of the ye and surrounding structures.

The tool has some merits for developing countries, but should not be used as an alternative to a proper eye test where possible, just for the sake of saving a few quid!

[p0rt1337]

The problem with this is that it does not "binocularly balance" the eyes. Therefore there is a risk of a muscle imbalance if specs are made in this fashion, causing stains and headaches, especially for near vision tasks.

[demlasjr]

@ndawg25 I'm not sure this gadget is free :)